The present embodiments relate to medical assessment of heart function. Heart function is assessed with any of a variety of imaging modalities and/or signals obtained by external scanning or measurements. Pressure, pressure-volume loops in particular, has been shown to characterize cardiac function and the efficiency of pump function. However, intra-cardiac pressure measurement requires invasive examination where a pressure catheter is inserted into the cavity.
Imaging may be used to obtain some pressure information. Flow imaging (e.g. Color Doppler ultrasound or phase-contrast magnetic resonance imaging (MRI)) is a common surrogate, enabling the computation of pressure gradients. Yet, the images or scan data used to compute pressure gradients have sources of inaccuracy, such as being unidirectional (ultrasound-based) or being planar (2D PC-MRI) instead of including a three-dimensional pressure or having poor spatial and/or temporal resolution (3D PC-MRI). Furthermore, flow provides only information on pressure gradient (e.g. pressure drop across a valve), but not the absolute pressure. On the other hand, invasive pressure and pressure-volume measurements are sensitive to the position of the catheter inside the heart and to noise.